Other GOP lawmakers, however, expressed concerns that a provision in the law hurt Republicans in high-tax states such as New York and New Jersey — where the GOP ended up losing a total of six seats, with two races still uncalled.

The law, which cut tax rates across-the-board for individuals and businesses, was unpopular at the time it was signed, but Republicans thought it would become a political winner as people started seeing more money in their paychecks.

The law’s popularity increased in the weeks following its enactment, when many companies announced that they were giving their employees bonuses. But the tax law never got widespread support, and polls ahead of the election tended to show voters divided on the measure.

While Republicans spent some time on the campaign trail touting the tax cuts and arguing that Democrats would raise taxes if elected, other issues, such as immigration, often featured more prominently in their campaigns.

“To properly message the tax law, it takes a lot of time and effort, and you have to stay on the same page,” said GOP strategist Ford O’Connell.

Democrats campaigned against the law and say their message that it primarily benefited wealthy individuals and corporations resonated with voters. An internal Republican National Committee poll in September found that most people thought the law helped the wealthy and corporations more than the middle class.

Health care was a bigger part of Democratic campaigns, though the two issues were linked to some extent, with Democrats often arguing that the tax law’s increase in the debt would lead Republicans to pursue cuts in social safety net programs like Medicare.

Democrats ended up gaining more than 30 House seats. These gains involved defeating four Republicans on the Ways and Means Committee and flipping a number of seats in high-tax states such as New York, New Jersey, California and Illinois that were particularly affected by the tax law’s $10,000 cap on the state and local tax (SALT) deduction.

Of the 11 House Republicans who voted against the tax law because of concerns about the SALT deduction cap, four lost and another three retired and will have Democratic successors.

Some Republicans in suburban districts in high-tax states said that the SALT deduction cap was a factor in GOP losses.

The affluent districts that contain many voters who claim the SALT deduction also are areas where Trump was unpopular, and some strategists see the overall displeasure at the president as a bigger reason why these districts went for Democrats.

“Republicans suffered big losses in high-tax states where the SALT cap affected a lot of voters,” said Dave Wasserman, House editor for the nonpartisan Cook Political Report.

Still, he said it’s difficult to completely assess blame since other factors also could have contributed to GOP losses in those areas.

Wasserman said “it’s difficult to discern the impact because those are places where Trump did worse in 2016.”

Some political observers think GOP efforts to repeal and replace ObamaCare, which were ultimately unsuccessful, ended up playing a bigger role. Exit-poll data found that a plurality of voters saw health care as the most important issue.

But Patrick Murray, director of the Monmouth University Polling Institute, said that the fact that the tax law wasn’t a prominent issue in and of itself was a problem for Republicans, because it meant that Republicans felt like they couldn’t focus on their biggest piece of legislation.

“They couldn’t really run on their signature issue because the public was really divided,” he said.